/* Copyright 2020 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 *
 * PD chip Crypress 5525 driver
 */
#include "config.h"
#include "console.h"
#include "task.h"
#include "hooks.h"
#include "uart.h"
#include "util.h"
#include "spi_flash.h"

#include "system_serial.h"
#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ##args)

#define SLOT_A_ADDRESS (0x3D000)
#define SLOT_B_ADDRESS (0x3E000)
#define SLOT_INVALID (-1)
/**
 * The type of the CRC values.
 *
 * This type must be big enough to contain at least 32 bits.
 */
typedef uint_fast32_t crc_t;

/**
 * Calculate the initial crc value.
 *
 * \return     The initial crc value.
 */
static inline crc_t crc_init(void)
{
	return 0xffffffff;
}

/**
 * Static table used for the table_driven implementation.
 */
static const crc_t crc_table[256] = {
	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
	0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
	0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
	0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
	0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

crc_t crc_update(crc_t crc, const void *data, size_t data_len)
{
	const unsigned char *d = (const unsigned char *)data;
	unsigned int tbl_idx;

	while (data_len--) {
		tbl_idx = (crc ^ *d) & 0xff;
		crc = (crc_table[tbl_idx] ^ (crc >> 8)) & 0xffffffff;
		d++;
	}
	return crc & 0xffffffff;
}

/**
 * Calculate the final crc value.
 *
 * \param[in] crc  The current crc value.
 * \return     The final crc value.
 */
static inline crc_t crc_finalize(crc_t crc)
{
	return crc ^ 0xffffffff;
}

static struct ec_flash_serial_info serials_info = {

};
static int current_slot = SLOT_INVALID;

int write_slot(int address)
{
	int i;

	if (spi_flash_erase(address, 0x1000) != EC_SUCCESS) {
		CPRINTS("Failed Erase");
		return EC_ERROR_INVAL;
	}
	for (i = 0; i < sizeof(serials_info); i += 256) {
		spi_flash_write(address + i, MIN(256, i - sizeof(serials_info)),
				(void *)(&serials_info) + i);
	}
	current_slot = address;
	return EC_SUCCESS;
}

int read_slot(int address)
{
	int i;

	for (i = 0; i < sizeof(serials_info); i += 256) {
		spi_flash_read((void *)(&serials_info) + i, address + i,
			       MIN(256, i - sizeof(serials_info)));
	}
	return EC_SUCCESS;
}

int validate_serial_structure(int address)
{
	crc_t crc;

	CPRINTS("Checking serials at 0x%x", address);
	read_slot(address);

	if (serials_info.magic != 0xF5A3E) {
		CPRINTS("Invalid Magic");
		return -1;
	}
	if (serials_info.version != 0x1) {
		CPRINTS("Unknown version");
		return -1;
	}
	if (serials_info.length != sizeof(serials_info) - 8) {
		CPRINTS("Invalid length");
		return -1;
	}
	crc = crc_init();
	crc = crc_update(crc, &serials_info, sizeof(serials_info) - 4);
	crc = crc_finalize(crc);
	/*we assume we have not crossed a read boundry for the crc
	 * but this is not clean pointer math at the moment
	 * */
	if (crc != serials_info.crc) {
		CPRINTS("Invalid CRC");
		return -1;
	}
	CPRINTS("Valid!");

	return serials_info.update_number;
}

int get_valid_slot(void)
{
	int slot_a;
	int slot_b;

	slot_a = validate_serial_structure(SLOT_A_ADDRESS);
	slot_b = validate_serial_structure(SLOT_B_ADDRESS);
	if (slot_a == SLOT_INVALID && slot_b == SLOT_INVALID) {
		return SLOT_INVALID;
	}
	if (slot_a > slot_b) {
		current_slot = SLOT_A_ADDRESS;
		read_slot(SLOT_A_ADDRESS);
		return SLOT_A_ADDRESS;
	}
	current_slot = SLOT_B_ADDRESS;
	return SLOT_B_ADDRESS;
}

int initialize_structure(void)
{
	crc_t crc;

	memset(&serials_info, 0x00, sizeof(serials_info));
	serials_info.magic = 0xF5A3E;
	serials_info.version = 1;
	serials_info.update_number = 0;
	serials_info.length = sizeof(serials_info) - 8;
	crc = crc_init();
	crc = crc_update(crc, &serials_info, sizeof(serials_info) - 4);
	serials_info.crc = crc_finalize(crc);

	return EC_SUCCESS;
}
int update_serial(int idx, char *serial)
{
	crc_t crc;
	int new_slot;

	if (idx >= SN_MAX) {
		return EC_ERROR_PARAM1;
	}
	if (current_slot == SLOT_INVALID) {
		initialize_structure();
	}

	strncpy(serials_info.serials[idx], serial, SERIAL_STR_SIZE);
	serials_info.update_number++;
	crc = crc_init();
	crc = crc_update(crc, &serials_info, sizeof(serials_info) - 4);
	serials_info.crc = crc_finalize(crc);

	if (current_slot == SLOT_A_ADDRESS) {
		new_slot = SLOT_B_ADDRESS;
	} else {
		new_slot = SLOT_A_ADDRESS;
	}
	write_slot(new_slot);
	return EC_SUCCESS;
}

int print_serial(int address)
{
	int i;
	int update_number;

	update_number = validate_serial_structure(address);

	CPRINTS("  Magic: 0x%04x", serials_info.magic);
	CPRINTS(" Length: 0x%04x", serials_info.length);
	CPRINTS("Version: 0x%04x", serials_info.version);
	CPRINTS(" Update: 0x%04x", serials_info.update_number);
	CPRINTS("    CRC: 0x%04x %s", serials_info.crc,
		update_number == -1 ? "Invalid" : "Valid");
	if (update_number != -1) {
		for (i = 0; i < SN_MAX; i++) {
			CPRINTS("Serial %02d: %s", i, serials_info.serials[i]);
			cflush();
		}
	}

	return read_slot(current_slot); /*reload valid slot*/
}

static int cmd_systemserial(int argc, char **argv)
{
	int i;
	char *e;
	char *serial;
	int valid;

	valid = get_valid_slot();
	if (argc == 1) {
		CPRINTS("  Current valid slot: 0x%04x", valid);

		/*we are verifying the serial data structure*/
		print_serial(SLOT_A_ADDRESS);

		print_serial(SLOT_B_ADDRESS);
	}
	if (argc == 3) {
		/* we are writing a new serial number*/
		i = strtoi(argv[1], &e, 0);
		serial = argv[2];
		update_serial(i, serial);
	}
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(systemserial, cmd_systemserial,
			"verify | [index] [new serial]",
			"verify system serial data structure");
